/*
 * Copyright (C) 2008 The Android Open Source Project
 * Copyright (C) 2014 The Linux Foundation. All rights reserved.
 * Copyright (C) 2016 The CyanogenMod Project
 * Copyright (C) 2017 The LineageOS Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "lights"

#include <cutils/log.h>

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>

#include <sys/ioctl.h>
#include <sys/types.h>

#include <hardware/lights.h>

#ifndef DEFAULT_LOW_PERSISTENCE_MODE_BRIGHTNESS
#define DEFAULT_LOW_PERSISTENCE_MODE_BRIGHTNESS 0x80
#endif

static pthread_once_t g_init = PTHREAD_ONCE_INIT;
static pthread_mutex_t g_lock = PTHREAD_MUTEX_INITIALIZER;

static struct light_state_t g_attention;
static struct light_state_t g_notification;
static struct light_state_t g_battery;
static int g_last_backlight_mode = BRIGHTNESS_MODE_USER;

#define BUTTON_1_BRIGHTNESS_FILE "/sys/class/leds/button-backlight/brightness"
#define BUTTON_2_BRIGHTNESS_FILE "/sys/class/leds/button-backlight1/brightness"

enum buttons_mask_t {
    BUTTON_1 = 0x1,
    BUTTON_2 = 0x2,
};

static int hw_buttons;

#define LCD_BRIGHTNESS_FILE "/sys/class/leds/lcd-backlight/brightness"
#define LCD_MAX_BRIGHTNESS_FILE "/sys/class/leds/lcd-backlight/max_brightness"

#define WHITE_LED_BRIGHTNESS_FILE "/sys/class/leds/white/brightness"

#define WHITE_DUTY_PCTS_FILE "/sys/class/leds/white/duty_pcts"

#define WHITE_START_IDX_FILE "/sys/class/leds/white/start_idx"

#define WHITE_PAUSE_LO_FILE "/sys/class/leds/white/pause_lo"

#define WHITE_PAUSE_HI_FILE "/sys/class/leds/white/pause_hi"

#define WHITE_RAMP_STEP_MS_FILE "/sys/class/leds/white/ramp_step_ms"

#define WHITE_BLINK_FILE "/sys/class/leds/white/blink"

char const*const PERSISTENCE_FILE
        = "/sys/class/graphics/fb0/msm_fb_persist_mode";

#define RAMP_SIZE 8
static int BRIGHTNESS_RAMP[RAMP_SIZE] = { 0, 12, 25, 37, 50, 72, 85, 100 };
#define RAMP_STEP_DURATION 50

#define DEFAULT_MAX_BRIGHTNESS 255
int max_brightness;

/**
 * Device methods
 */

void check_buttons_support()
{
    // Assume that the device has at least two buttons
    hw_buttons = BUTTON_1 | BUTTON_2;
}

static void init_globals(void)
{
    // Init the mutex
    pthread_mutex_init(&g_lock, NULL);
}

static int read_int(char const* path)
{
    int fd, len;
    int num_bytes = 10;
    char buf[11];
    int retval;

    fd = open(path, O_RDONLY);
    if (fd < 0) {
        ALOGE("%s: failed to open %s\n", __func__, path);
        goto fail;
    }

    len = read(fd, buf, num_bytes - 1);
    if (len < 0) {
        ALOGE("%s: failed to read from %s\n", __func__, path);
        goto fail;
    }

    buf[len] = '\0';
    close(fd);

    // no endptr, decimal base
    retval = strtol(buf, NULL, 10);
    return retval == 0 ? -1 : retval;

fail:
    if (fd >= 0)
        close(fd);
    return -1;
}

static int write_int(char const* path, int value)
{
    int fd;
    static int already_warned = 0;

    fd = open(path, O_RDWR);
    if (fd >= 0) {
        char buffer[20];
        int bytes = snprintf(buffer, sizeof(buffer), "%d\n", value);
        ssize_t amt = write(fd, buffer, (size_t)bytes);
        close(fd);
        return amt == -1 ? -errno : 0;
    } else {
        if (already_warned == 0) {
            ALOGE("%s: failed to open %s\n", __func__, path);
            already_warned = 1;
        }
        return -errno;
    }
}

static int write_str(char const* path, char* value)
{
    int fd;
    static int already_warned = 0;

    fd = open(path, O_RDWR);
    if (fd >= 0) {
        char buffer[1024];
        int bytes = snprintf(buffer, sizeof(buffer), "%s\n", value);
        ssize_t amt = write(fd, buffer, (size_t)bytes);
        close(fd);
        return amt == -1 ? -errno : 0;
    } else {
        if (already_warned == 0) {
            ALOGE("%s: failed to open %s\n", __func__, path);
            already_warned = 1;
        }
        return -errno;
    }
}

static int is_lit(struct light_state_t const* state)
{
    return state->color & 0x00ffffff;
}

static int rgb_to_brightness(struct light_state_t const* state)
{
    int color = state->color & 0x00ffffff;

    return ((77 * ((color >> 16) & 0x00ff))
            + (150 * ((color >> 8) & 0x00ff)) + (29 * (color & 0x00ff))) >> 8;
}

static int set_light_backlight(struct light_device_t* dev,
        struct light_state_t const* state)
{
    int err = 0;
    int brightness = rgb_to_brightness(state);
    unsigned int lpEnabled =
        state->brightnessMode == BRIGHTNESS_MODE_LOW_PERSISTENCE;

    if (!dev)
        return -1;

    // If max panel brightness is not the default (255),
    // apply linear scaling across the accepted range.
    if (max_brightness != DEFAULT_MAX_BRIGHTNESS) {
        int old_brightness = brightness;
        brightness = brightness * max_brightness / DEFAULT_MAX_BRIGHTNESS;
        ALOGV("%s: scaling brightness %d => %d\n", __func__, old_brightness, brightness);
    }

    pthread_mutex_lock(&g_lock);
    // Toggle low persistence mode state
    if ((g_last_backlight_mode != state->brightnessMode && lpEnabled) ||
        (!lpEnabled &&
         g_last_backlight_mode == BRIGHTNESS_MODE_LOW_PERSISTENCE)) {
        if ((err = write_int(PERSISTENCE_FILE, lpEnabled)) != 0) {
            ALOGE("%s: Failed to write to %s: %s\n", __FUNCTION__,
                   PERSISTENCE_FILE, strerror(errno));
        }
        if (lpEnabled != 0) {
            brightness = DEFAULT_LOW_PERSISTENCE_MODE_BRIGHTNESS;
        }
    }

    g_last_backlight_mode = state->brightnessMode;

    if (!err) {
        err = write_int(LCD_BRIGHTNESS_FILE, brightness);
    }

    pthread_mutex_unlock(&g_lock);
    return err;
}

static int set_light_buttons(struct light_device_t *dev,
        const struct light_state_t *state)
{
    int err = 0;
    int brightness = rgb_to_brightness(state);

    if (!dev)
        return -1;

    pthread_mutex_lock(&g_lock);

    if (hw_buttons & BUTTON_1)
        err += write_int(BUTTON_1_BRIGHTNESS_FILE, brightness);
    if (hw_buttons & BUTTON_2)
        err += write_int(BUTTON_2_BRIGHTNESS_FILE, brightness);

    pthread_mutex_unlock(&g_lock);
    return err;
}

static char* get_scaled_duty_pcts(int brightness)
{
    char *buf = malloc(5 * RAMP_SIZE * sizeof(char));
    char *pad = "";
    int i = 0;

    memset(buf, 0, 5 * RAMP_SIZE * sizeof(char));

    for (i = 0; i < RAMP_SIZE; i++) {
        char temp[5] = "";
        snprintf(temp, sizeof(temp), "%s%d", pad, (BRIGHTNESS_RAMP[i] * brightness / 255));
        strcat(buf, temp);
        pad = ",";
    }
    ALOGV("%s: brightness=%d, duty=%s\n", __func__, brightness, buf);
    return buf;
}

static int set_speaker_light_locked(struct light_device_t* dev,
        struct light_state_t const* state)
{
    int white, blink;
    int onMS, offMS, stepDuration, pauseHi;
    char *duty;

    if (!dev)
        return -1;

    switch (state->flashMode) {
    case LIGHT_FLASH_TIMED:
        onMS = state->flashOnMS;
        offMS = state->flashOffMS;
        break;
    case LIGHT_FLASH_NONE:
    default:
        onMS = 0;
        offMS = 0;
        break;
    }

    ALOGV("%s: mode %d, colorRGB=%08X, onMS=%d, offMS=%d\n",
            __func__, state->flashMode, state->color, onMS, offMS);

    white = rgb_to_brightness(state);
    blink = onMS > 0 && offMS > 0;

    write_int(WHITE_BLINK_FILE, 0);

    if (blink) {
        stepDuration = RAMP_STEP_DURATION;
        pauseHi = onMS - (stepDuration * RAMP_SIZE * 2);
        if (stepDuration * RAMP_SIZE * 2 > onMS) {
            stepDuration = onMS / (RAMP_SIZE * 2);
            pauseHi = 0;
        }

        // white
        write_int(WHITE_START_IDX_FILE, 0);
        duty = get_scaled_duty_pcts(white);
        write_str(WHITE_DUTY_PCTS_FILE, duty);
        write_int(WHITE_PAUSE_LO_FILE, offMS);
        // The led driver is configured to ramp up then ramp
        // down the lut. This effectively doubles the ramp duration.
        write_int(WHITE_PAUSE_HI_FILE, pauseHi);
        write_int(WHITE_RAMP_STEP_MS_FILE, stepDuration);
        free(duty);

	write_int(WHITE_BLINK_FILE, 1);

    } else {
        if (white == 0 ) {
            write_int(WHITE_BLINK_FILE, 0);
        }
        write_int(WHITE_LED_BRIGHTNESS_FILE, white);
    }

    return 0;
}

static void handle_speaker_light_locked(struct light_device_t* dev)
{
    if (is_lit(&g_attention))
        set_speaker_light_locked(dev, &g_attention);
    else if (is_lit(&g_notification))
        set_speaker_light_locked(dev, &g_notification);
    else
        set_speaker_light_locked(dev, &g_battery);
}

static int set_light_battery(struct light_device_t* dev,
        struct light_state_t const* state)
{
    pthread_mutex_lock(&g_lock);
    g_battery = *state;
    handle_speaker_light_locked(dev);
    pthread_mutex_unlock(&g_lock);
    return 0;
}

static int set_light_notifications(struct light_device_t* dev,
        struct light_state_t const* state)
{
    pthread_mutex_lock(&g_lock);

    unsigned int brightness;
    unsigned int color;
    unsigned int rgb[3];

    g_notification = *state;

    // If a brightness has been applied by the user
    brightness = (g_notification.color & 0xFF000000) >> 24;
    if (brightness > 0 && brightness < 0xFF) {

        // Retrieve each of the RGB colors
        color = g_notification.color & 0x00FFFFFF;
        rgb[0] = (color >> 16) & 0xFF;
        rgb[1] = (color >> 8) & 0xFF;
        rgb[2] = color & 0xFF;

        // Apply the brightness level
        if (rgb[0] > 0)
            rgb[0] = (rgb[0] * brightness) / 0xFF;
        if (rgb[1] > 0)
            rgb[1] = (rgb[1] * brightness) / 0xFF;
        if (rgb[2] > 0)
            rgb[2] = (rgb[2] * brightness) / 0xFF;

        // Update with the new color
        g_notification.color = (rgb[0] << 16) + (rgb[1] << 8) + rgb[2];
    }

    handle_speaker_light_locked(dev);
    pthread_mutex_unlock(&g_lock);
    return 0;
}

static int set_light_attention(struct light_device_t* dev,
        struct light_state_t const* state)
{
    pthread_mutex_lock(&g_lock);
    g_attention = *state;
    handle_speaker_light_locked(dev);
    pthread_mutex_unlock(&g_lock);
    return 0;
}

/** Close the lights device */
static int close_lights(struct light_device_t *dev)
{
    if (dev)
        free(dev);
    return 0;
}


/**
 * Module methods
 */

/** Open a new instance of a lights device using name */
static int open_lights(const struct hw_module_t* module, char const* name,
        struct hw_device_t** device)
{
    int (*set_light)(struct light_device_t* dev,
            struct light_state_t const* state);

    check_buttons_support();

    if (0 == strcmp(LIGHT_ID_BACKLIGHT, name))
        set_light = set_light_backlight;
    else if (0 == strcmp(LIGHT_ID_BUTTONS, name))
        set_light = set_light_buttons;
    else if (0 == strcmp(LIGHT_ID_BATTERY, name))
        set_light = set_light_battery;
    else if (0 == strcmp(LIGHT_ID_NOTIFICATIONS, name))
        set_light = set_light_notifications;
    else if (0 == strcmp(LIGHT_ID_ATTENTION, name))
        set_light = set_light_attention;
    else
        return -EINVAL;

    max_brightness = read_int(LCD_MAX_BRIGHTNESS_FILE);
    if (max_brightness < 0) {
        ALOGE("%s: failed to read max panel brightness, fallback to 255!\n", __func__);
        max_brightness = DEFAULT_MAX_BRIGHTNESS;
    }

    pthread_once(&g_init, init_globals);

    struct light_device_t *dev = malloc(sizeof(struct light_device_t));

    if (!dev)
        return -ENOMEM;

    memset(dev, 0, sizeof(*dev));

    dev->common.tag = HARDWARE_DEVICE_TAG;
    dev->common.version = 0;
    dev->common.module = (struct hw_module_t*)module;
    dev->common.close = (int (*)(struct hw_device_t*))close_lights;
    dev->set_light = set_light;

    *device = (struct hw_device_t*)dev;
    return 0;
}

static struct hw_module_methods_t lights_module_methods = {
    .open =  open_lights,
};

/*
 * The lights Module
 */
struct hw_module_t HAL_MODULE_INFO_SYM = {
    .tag = HARDWARE_MODULE_TAG,
    .version_major = 1,
    .version_minor = 0,
    .id = LIGHTS_HARDWARE_MODULE_ID,
    .name = "Xiaomi msm8998 Lights Module",
    .author = "The CyanogenMod Project",
    .methods = &lights_module_methods,
};
